MILWAUKEE (AP) — An Iraq War veteran who initially pleaded insanity in the fatal shooting of his wife, a Milwaukee-area police officer, instead changed his plea to guilty Wednesday after two doctors concluded that his mental-health issues weren’t severe enough to justify an insanity plea.

Benjamin G. Sebena, 30, was accused of ambushing his wife, 30-year-old Jennifer Sebena, on Christmas Eve as the Wauwatosa police officer conducted a solo pre-dawn patrol. He told investigators he was a jealous husband and had been stalking her.

Ben Sebena, charged with first-degree intentional homicide, initially pleaded not guilty by reason of mental disease or defect. But two separate doctors said that while the former Marine suffers from post-traumatic stress disorder and other issues, he wasn’t insane at the time of the crime.

In exchange for his guilty plea, prosecutors have agreed to recommend that Sebena be eligible for parole in 50 to 60 years. A conviction of first-degree intentional homicide carries a mandatory life sentence but a judge could allow for parole after 20 years.

Defense attorney Michael Steinle said it was Sebena’s idea to plead guilty, and that he’d been considering doing so for the last month or more.

“Quite honestly, he wants to get the decision done as quickly as possible,” Steinle said.

As with every court appearance he has made, Sebena was brought into court in a wheelchair and wearing a padded suicide-prevention vest. He was silent except when entering his plea and responding to Judge David Borowski’s questions.

The judge asked whether Sebena understood that his guilty plea meant he was acknowledging that he killed his wife, and that he meant to do so.

“Yes, sir,” Sebena replied in a clear unwavering voice.

Steinle left court without talking to reporters. Sebena’s family also declined to speak to reporters.

Sebena was due to face trial next month, at which point prosecutors would certainly have introduced incriminating statements Sebena made to police.

He had acknowledged lying in wait for his wife outside the fire department where officers often take their breaks. He said he saw her and opened fire, and when she reached for her weapon he grabbed it from her holster and used it to shoot her in the face three or four times. He told investigators he wanted to make sure she was dead so she wouldn’t suffer.

Jennifer Sebena had told a colleague a few weeks before her death that her husband had acted violently toward her and put a gun to her head, prosecutors said. Detectives who searched the couple’s home found a gun with ammunition matching the bullet casings found at the scene. They also found Jennifer Sebena’s service weapon stashed in the attic.

Ben Sebena’s defense attorney, Michael Steinle, tried to have some of Sebena’s comments to police thrown out because officers hadn’t immediately informed him he had the rights to remain silent and have an attorney present. But Judge David Borowski ruled last week that police didn’t need to read him his Miranda rights immediately because he didn’t become a suspect until later.

Ben Sebena served two tours in Iraq with the U.S. Marine Corps. He was honorably discharged in 2005 after suffering severe arm and leg injuries in a mortar attack.